Safety air gun



Dec. 15, 1959 R. L. GOULD 2,917,244

SAFETY AIR GUN Filed Aug. 29, 1957 VII/11111 Z I INVENTOR. RALPH L. BUULD ATTUENEY United States Patent SAFETY AIR GUN Ralph L. Gould, Milford, Conn.

Application August 29, 1957, Serial No. 681,008

1 Claim. (Cl. 239-291) The present invention relates to a safety air gun, particularly of the type for use in various shops and industrial plants for removing chips, shavings, or the like, produced by cutting operations, as well as for general machine cleaning and blowing operations. The conventional type of air gun employs a high pressure air jet to disperse the material to be removed, and in certain operations, for instance, when such material is disposed in a hole or recess, the air jet causes the material to be deflected upwardly, often resulting in eye injuries. It is proposed in the present invention to provide an improved type of air shield which surrounds a central air jet to provide an air barrier against the upward deflection of chips or the like by the central air jet.

Heretofore it has been proposed to provide a conical air shield directed through a narrow annular inclined slot, the air being dispersed in a relatively thin conical layer having substantially less pound pressure than the pressure of the air jet, so that high velocity chips would sometimes penetrate the air shileld. It is an object of the present invention to provide an improved air shield in the form of a series of high pressure auxiliary jets directed in a swirling cyclonic path of forwardly divergent shape and of such depth and pressure that chips deflected by the central main air jet will be taken up in the swirl of the air shield and directed downwardly as well as in a lateral direction, thus effectually preventing the upward deflection of such chips to any considerable distance.

Other objects and advantages of the invention will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawing wherein a satisfactory embodiment of the invention is shown. However, it will be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claim.

In the drawing:

Fig. 1 is a side elevation of a safety air gun, according to the illustrated exemplary embodiment of the invention;

Fig. 2 is a rear end elevation;

Fig. 3 is a top plan view;

Fig. 4 is a longitudinal vertical sectional view taken along the line 44 of Fig. 3;

Fig. 5 is a transverse vertical sectional view taken along the line 5-5 of Fig. 4;

Fig. 6 is a side elevation of the nozzle part of the air gun;

Fig. 7 is a front end elevation of the nozzle as seen in Fig. 6;

Fig. 8 is a rear end elevation of the nozzle as seen in Fig. 5;

Fig. 9 is a perspective view from the rear looking in the direction indicated by the arrows in Fig. 6;

Fig. 10 is a diagrammatic perspective view showing the direction of the air jet and air shield in the operation of the air gun.

2,917,244 Patented Dec. 15, 1959 Referring to the drawings, the safety air gun, according to the illustrated exemplary embodiment of the invention, comprises a nozzle body including a housing member 10 preferably in the form of a casting, and consisting of a forward cylindrical barrel portion 11, an intermediate valve portion 12 and a rearward hose attaching tubular portion 13, the latter having a central air passage 14 provided at its rearward end with a threaded portion 15 for the attachment by a suitable nipple of a high pressure air hose.

The barrel portion 11 is adapted to receive the nozzle part, as will presently more fully appear, and high pressure air is directed to the interior of the barrel through a control valve which is illustrated as of the push button spring loaded type, although it will beunderstood that any suitable type of valve may be employed. The valve portion 12 is provided with a horizontal passage 16 extending axially from the barrel portion 11 to a vertical air chamber 17 having an upper Wall portion 18 provided with a valve stem passage 19, an annular valve seat 20 being provided at the lower end of the chamber 17. An inclined passage 21 extends from the passage 14 to a valve pocket 22 below the valve seat, and in the lower end of which there is screwed a threaded closure cap 23.

The valve consists of a valve stem 24 slidably engaged in the passage 19 and provided at its upper end with a push buton 25 movable in a pocket 26 at the upper side of the wall 18, a valve closure member 27 of rubber or other suitable material being secured upon the stem for engagement with the valve seat, and the stem being provided beneath the valve closure member with an extension pin portion 28 movable in a pocket 29 of the closure cap 23. A helical spring 30 is disposed in the pocket 29 about the pin 28 and normally exerts upward pressure upon the valve to seat the closure member against the valve seat 20. Upon pressing the button 25 downwardly the valve is opened to allow air to pass from the passage 21 into the air chamber 17 and thence through the passage 16 to the barrel portion 11.

The nozzle part 31 of the nozzle body comprises a forward tapered portion 32 having a rearward annular shoulder 33 which abuts the forward end of the barrel portion 11, and rearward cylindrical plug portion 34 adapted to fit within the barrel portion 11. A cylindrical main air jet passage 35 extends through the nozzle and is threaded at its forward end, as at 36, to receive an air jet tip 37 having a central reduced air jet passage 38. This tip is readily removable so that, if desired, it can be replaced by tips of varying lengths, it being desirable in certain cleaning operations to have a relatively long tip.

The inner end of the plug portion 34 is spaced from the inner end of the barrel portion to provide an enlarged air space 39 between the passage 16 extending from the valve chamber 17 and the passage 35 through the nozzle, for a purpose presently to more fully appear.

The nozzle part is provided exteriorly with a series of grooves 40 extending along the plug portion 34 from its rearward end through the shoulder 33 and terminating forwardly of theshoulder in the forward tapered portion 32. These grooves are equally spaced about the nozzle part and extend in straight lines from their rearward to their forward ends, their bases being disposed in tangential planes parallel to the central axis of the nozzle and their direction being at an oblique angle to the axis of the nozzle. As clearly illustrated in Figs. 6 and 9 the grooves 40 are straight cuts, and may be conveniently produced by a straight milling cut. In the illustrated example of the invention four such grooves are provided, so that their bases lie in the planes of the sides of a foursided straight block, as indicated in the diagrammatic 3 illustration in Fig. 10. It will be understood, however, that any desired number of grooves may be provided in equally spaced relation to the nozzle.

r When the plug portion 34 of the nozzle part is assembled in the :barrel 11 the grooves 40 each form an inclined auxiliary air jet passage extending from the air space 39 at the rearward end of the nozzle to the forward terminal of the groove in the forward tapered portion 32 of the. nozzle, the forward end of the groove opening directly to the atmosphere without any forward obstruction to the jet of air directed therefrom, so that the jet of air will be directed through and from the inclined passage with its center in a plane parallel to the axis of the central jet passage 38 and at a forward diverging angle thereto. As clearly indicated in Fig. 10, wherein a rectangular block represents the nozzle, the plurality of air jets directed from the plurality of passages 40 about the nozzle surround the central main air jet directed from the central passage 38 as a divergent air shield in which the air is directed in a swirling cyclonic path. As each jet emerges it spreads so that the individual air jets merge at a relatively short distance from the end of the nozzle, which in practice has been found to be about six to eight inches in the case of a nozzle having substantially the proportions illustrated in the drawings and wherein the outside diameter of the barrel portion 11 is. about one inch. Also the dimensions of the air jet passage 40 with relation to the central air jet passage 38 are preferably such that the surrounding air jets producing the swirling shield have greater pressure than the central air jet directed through passage 38, with the result that chips and particles propelled by the central air jet are effectually prevented from penetrating the air shield.

The plug portion 34 is secured within the barrel portion 11 by a tapered pin 41 engaged through suitable holes 42 in the barrel and 43 in the plug portion, the positioning of the pin being such that it clears the passages 40 and extends diametrically across the passage 35. It is understood that any suitable fastening means may be employed.

What is claimed is:

In a safety air gun for removing chips or the like from a machine surface or the like, a nozzle body having: a central air jet passage having a rearward inlet end and a forward discharge end and extending longitudinally of said body along a straight line central axis to direct a central air jet in a straight line forwardly therefrom; a plurality of circumferentially equidistantly spaced auxiliary air jet passages in outwardly equidistantly spaced surrounding relation to said central passage having rearward inlet ends and forward discharge ends, and extending along straight line axes at equal and directionally uniform oblique angles to said central axis and lying in planes parallel to said central axis to direct oblique air jets in straight lines forwardly therefrom; and air inlet means in communication with said inlet ends of said central and auxiliary air jet passages; said forward discharge ends of said auxiliary air jet passages opening directly to the atmosphere in a forward surface of said body free of obstruction to the forward straight line paths of said oblique air jets whereby a divergent high pressure air shield of obliquely directed air jets is produced in outwardly spaced relation to said central air jet with a gradually widening low pressure air space betweensaid central air jet and said air shield through which chips or the like propelled from said machine surface or the like by said central air jet may move into the' path of said shield.

References Cited in the file of this patent UNITED STATES PATENTS 625,466 Randolph May 23, 1899 2,783,092 Gavin et al Feb. 26, 1957 FOREIGN PATENTS 458,315 Germany Apr. 3, 1928 

